<!DOCTYPE html>
<html>
	<head>
		<title></title>
	</head>
	<body>
		<script>
			var x=prompt("请输入一个字符：");
			x=x.charCodeAt(0);
			if(x>=48&&x<=57)
			{
				document.write("这是数字");
			}
			else if(x>=65&&x<=90)
			{
				document.write("这是大写字母");
			}
			else if(x>=97&&x<=122)
			{
				document.write("这是小写字母");
			}
			else
			{
				document.write("这是符号");
			}
			</script>
	</body>
</html>